In an apparatus, such as a laser machining apparatus, a solid-state laser which is represented by a semiconductor excitation solid-state laser is used as a light source. That is, laser oscillation is caused by exciting a solid-state laser medium through light reflection, thereby obtaining a laser light.
In the oscillation medium (medium) which oscillates laser in this way, it is known that the temperature of the medium increases with an increase in laser output. Furthermore, it is known that, when the medium is cooled, a laser oscillation limit is improved. Accordingly, cooling of the laser oscillation medium is required.
As a technique for cooling the laser oscillation medium, for example, a technique described in PTL 1 is known.
PTL 1 describes a laser light generation device. In this device, in order to remove heat generated from a laser excitation device (BBO crystal device) with the generation of laser light, a configuration in which a cryogen, such as liquid nitrogen, accumulated in a heat insulation container is supplied to a cold finger thermally connected to the BBO crystal device is employed.